They upsized me the first time too and it was pretty rough. My bladder had spasms for a day and it felt like I was going to urinate normally (not possible with my stricture) at any given moment. Very disconcerting. Second time around it was little less painful but still got a UTI. Like you, anytime they fool with something I get sick. The Urethrogram put me in the ER 4 days later.
I have had the same nurse do it both times. She is good, but I don’t think there is anything she can do different. I think it is something you have to deal with. The antibiotics make me tired and a little nauseous at times. I will look forward to getting off of them.
I have a friend who is paraplegic and he went from a normal cath to SP and says it is much better. He tells me he had issues with infections early on but it has gotten better. Luckily I will lose mine in a month or so, if all goes well with the Urethroplasty.
Good luck with your issues and thanks for letting me know I am not alone in this new world I have entered. There are days it still seems like a bad dream I can’t wake up from.